Stud for a timber wall

ABSTRACT

The present invention relates to a stud ( 1 ) intended for a timber wall and a method for manufacturing the stud ( 1 ). The stud ( 1 ) constitutes a part of a wooden frame on which, for example, plaster board panels ( 12 ) are secured in order to form the wall. The stud ( 1 ) is provided with at least two longitudinal grooves ( 6, 7 ) made alternatingly from opposing sides ( 2, 3 ) of the stud ( 1 ). Each individual groove ( 6, 7 ) is wholly open towards that side ( 2, 3 ) it was made from. Each groove ( 6, 7 ) moreover displays openings ( 10, 11 ) in the opposite side ( 2, 3 ) and portions ( 8, 9 ) with residual material between the openings ( 10, 11 ). Each longitudinal groove ( 6, 7 ) is thus alternatingly through-going and alternatingly not through-going.

The present invention relates to a stud for a timber wall, and also to amethod for manufacturing the stud according to the preamble to theappended main claims.

The timber wall which the stud according to the present invention isintended for consists of panels, normally plaster board panels, securedon a wooden frame. The wooden frame normally consists of a sill or aground plate at the bottom, and a top plate at the top, with studsrunning between them. Plaster board panels or the like are then securedon this stud frame, on one or both sides. In door openings and the like,so-called nogging pieces are also mounted between the studs. A wall ofthis type should, int. al., be sound insulating and thermallyinsulating, this latter being particularly applicable to an outer wall.Naturally, the walls should also be as configurationally stable aspossible.

The present invention is based on the concept of making grooves in thestud in order to obtain improved properties as regards straightness,sound insulation and thermal insulation.

It has per se been previously known in the art to make, for differentreasons, grooves in studs. But the novel feature according to thepresent invention resides in the manner in which the grooves arearranged as well as how they are formed.

When sound is generated on one side of a timber wall of theabove-described type, the panels on that side of the wall are set inmotion. If the studs are homogeneous and relatively rigid, they transmitthe oscillation movement to the panel on the other side of the wallwithout any actual damping. A method of avoiding this sound transmissionis to render the studs less homogeneous and weaker so that theoscillations are not transmitted as easily between both sides of thewalls. The result of a less homogeneous and weaker stud will be improvedsound insulation. In the present invention, by placing groovesalternatingly from different directions, a stud will be obtained with anapproximately S-shaped cross section, the S-configuration making thestud resiliently yieldable in the direction between the panels, whilethe rigidity of the stud in other directions is affected to a lesserextent. Moreover, the grooves are compressed somewhat under the actionof physical force, which contributes to the sound insulation properties.As a result of the improved sound insulation, in certain cases thenecessity of building a thicker wall in order to give the desired soundinsulation is avoided.

Wood always absorbs and gives off water to and from its surroundingsdepending upon the air humidity, which influences the configurationalstability of the stud. When the moist ratio in the wood falls, itshrinks and when the moisture ratio rises the wood swells. Theseshrinkages and swellings are of different magnitude in differentdirections because the wood fibres lie in different directions. This inturn results in tension occurring in the wood. Many of these localtensions in the wood counteract one another, for which reason they giveno visible result, but a number of the local tensions cooperate whichmay result in the timber becoming bent and/or warped. By providinggrooves in the stud, many of the locally built-up tensions are reduced.Those tensions which remain result, after the provision of the groove,only in the width of the groove varying somewhat, which is of noimportance to the function of the stud.

For example, a through-going outer wall stud often acts as a cold bridgeeven though wood is a relatively good thermal insulator. Air, andparticularly motionless air, is however, a considerably better thermalinsulator. By providing the stud with grooves according to the presentinvention, there is at least one air column in every conceivable crosssection. This implies that the heat will have a considerably longerdistance to go when it must be spread in both the longitudinal andlateral directions.

One object of the present invention has thus been to develop a stud withimproved properties as regards straightness, sound insulation andthermal insulation.

Further objects and advantages according to the present invention willbe apparent from the following description of one preferred embodiment.Further advantageous embodiments of the present invention are disclosedin the appended subclaims. In the accompanying Drawings:

FIG. 1 is a perspective view of a section of a stud according to thepresent invention;

FIG. 2 is a cross section taken along the line II—II in FIG. 1, withplaster board panels intimated by broken lines;

FIG. 3 is a longitudinal section taken along the line III—III in FIG. 2;and

FIG. 4 is a top plan view of the stud section according to earlierFigures.

The stud 1 according to the present invention displays at least twolongitudinal grooves 6,7 taken from opposing sides 2,3 of the stud. Inother embodiments (not shown) more grooves are provided, where thegrooves lie alternatingly from opposing sides 2,3. The grooves 6,7 aremade on the sides 2,3 which are not intended to receive plaster boardpanels 12. When making the grooves 6,7 care should be taken to ensurethat they must lie a sufficient distance from the sides 4,5 of the stud1 in order that the screws (or nails) with which the panels 12 aresecured to the stud 1 do not enter into the grooves 6,7 or at least notthrough the grooves 6,7. Screws which go through the grooves 6,7 riskreducing the favourable properties attained thanks to the grooves. InFIG. 2, panels 12 are intimated as secured to the stud.

The grooves 6,7 are given a configuration which is such that each groove6,7 forms openings 10,11 on the opposing side 2,3 compared with thatdirection from which the grooves are made. Between these openings 10,11,the grooves 6,7 have portions 8,9 with residual material.

In the illustrated embodiment, the portions 8,9 with residual materialare of curved form. These grooves have been formed in that a rotary sawblade moves up and down through the stud 1 at the same time as the studmoves in the lateral direction.

On making the grooves 6,7, the amplitude of the vertical movement of thesaw blade is such that a turning point for the movement of the saw bladelies outside the lower or upper edge of the stud 1, depending uponwhether the grooves 6,7 are made from above or from below. The termturning point is here taken to signify that point at which the outerdiameter of the saw blade changes its vertical direction of movement.During a part of the movement of the blade, there will then be obtainedan entirely open groove while, during other parts of the movement of theblade, residual portions 8,9 with material will be left in place. Byvarying the diameter, vertical speed and amplitude of the saw blade aswell as the speed of advance of the stud, the groove configuration maybe varied.

In one alternative method, the grooves are made from alternatingly eachside with a saw blade operating without vertical movement, the openingsin the side opposite those sides where groove has been made being milledout. The result will be in this case that the stud (not shown) will havegrooves where the portions with residual material are of rectilinearform.

By coordinating the making of the grooves with planing of the stud,major production engineering advantages will be afforded.

The grooves 6,7 and the opposed openings 10,11 are given suchconfiguration that the openings 10,11 are of a longitudinal extent whichis greater than the longitudinal extent of the portions 8,9 withresidual material. By way of example excellent results have beenachieved when the longitudinal extent of the openings 10,11 were two tothree times as long as the longitudinal extent of the portions withresidual material. The fact that the openings 10,11 are of longerlongitudinal extent than the portions 8,9 with residual material entailsthat, when two or more grooves are provided, at least one groove in eachcross section has no residual material. This minimum of one groove isthus wholly open from the one longitudinal side 2 of the stud 1 to theother longitudinal side 3 in this cross section. There are crosssections where all grooves are wholly open between both longitudinalsides 2,3 of the stud 1, and there are also cross sections where one ormore grooves are wholly open and one or more grooves have residualmaterial. Taken as a whole, this implies that all cross sections of thestud 1 contain at least one wholly open groove forming an air gap.

In cross section, the residual material of the stud 1 when the grooves6,7 have been made, forms an approximately S-shape. As a result, thestud 1 will be “resiliently yieldable” in the direction of the soundpropagation from one side of the wall to the other side. The featurethat the grooves 6,7 are compressed under the action of force alsocontributes to this resilience, in which event the major portion of thecompression takes place in those parts of the grooves which havethough-going openings 10,11. This entails that the vibrations in onepanel 12 caused by sound waves are damped by the stud 1. With thegrooved stud according to the present invention, where the grooves havethrough-going openings, better sound insulation will thus be achievedthan if a traditional, homogeneous stud had been employed.

Since each cross section of the stud 1 includes at least one air gap, animproved thermal insulation will be obtained compared with a homogeneousstud or a stud with grooves which do not give at least one air gap ineach cross section. Since heat spreads more easily in the wood than inthe air, the heat will, because of the air gap, have a longer distanceto travel in that it must spread longitudinally and laterally past theair gap. The result will thus be improved thermal insulation.

The groove formation 6,7 in the stud 1 reduces the local tensions in thewood which lead to configurational changes, for which reason a moreconfigurationally stable stud will be obtained thanks to the grooves.

In the manufacture of the stud 1 according to the present invention, thestarting material is, after drying, taken to a plane where the stud isplaned to the desired dimensional accuracy. In connection with theplaning, the grooves 6,7 are made in the stud 1 as was intimated above.The plane and the saw blade lie in sequence after one another in thedirection of advancement of the stud, as a result of which grooves aremade at the same time as the planing operation is carried out. Incertain embodiments, several saw blades are employed simultaneously.

In the illustrated embodiment, we have taken as a point of departure astud which is normally employed in Sweden and has the dimensions 45×70mm. A person skilled in the art will readily perceive that the presentinvention may also be applied to a stud with other dimensions and otherrelationship between width and thickness. Thus, the present inventionmay be applied to all conceivable stud dimensions.

What is claimed is:
 1. A method for forming grooves in a timber stud (1)which is included in a wooden frame for walls, characterized in thatgrooves (6,7) are made alternatingly from two opposing sides (2,3) ofthe stud (1), said grooves (6,7) being wholly open towards that side(2,3) from which they are made; and that each groove (6,7) is providedwith through-going openings (10,11) to the opposing side (2,3) of thestud (1), whereby portions (8,9) having residual material are leftbetween the openings (10,11).
 2. The method as claimed in claim 1,characterized in that a reciprocal vertical movement is imparted to arotary saw blade at the same time as the stud (1) is advanced in thelongitudinal direction.
 3. The method as claimed in claim 2,characterized in that a turning point for the movement of the saw bladein the vertical direction lies outside the stud (1).
 4. The method asclaimed in claim 2, characterized in that the relationship between thevertical reciprocating movement of the saw blade and the speed of thestud (1) in the longitudinal direction is such that there are formedportions with curved form in the grooves (6,7).
 5. The method as claimedin claim 1, characterized in that the groove formation takes placesimultaneously with planing or other processing of the timber stud (1).6. The method as claimed in claim 1, characterized in that a pluralityof saw blades operates simultaneously in order to make a plurality ofgrooves (6,7) at one time.
 7. A timber stud (1) for use as a part in atimber frame intended to be clad with panels, characterized in that atleast two longitudinal grooves (6,7) are made in the longitudinaldirection of the stud (1); that the grooves (6,7) are made alternatinglyfrom opposing sides (2,3); and that each groove (6,7) displaysthrough-going openings (10,11) and portions (8,9) having residualmaterial between the through-going openings (10,11) in the grooves(6,7).
 8. The stud as claimed in claim 7, characterized in that thegrooves (6,7) are made such that an optional cross section of the stud(1) includes at least one air gap.
 9. The stud as claimed in claim 7,characterized in that portions (8,9) with residual material, between thethrough-going openings (10,11) in the grooves (6,7), have curvedconfiguration.